1. Field of the Invention
This invention relates to an electrophotographic image forming apparatus and a process cartridge.
Here, the process cartridge refers to charging means, developing means or cleaning means as process means and an electrophotographic photosensitive member integrally made into a cartridge which is made detachably mountable to the main body of an electrophotographic image forming apparatus. Or it refers to at least one of charging means, developing means and cleaning means as process means and an electrophotographic photosensitive member integrally made into a cartridge which is made detachably mountable to the main body of an electrophotographic image forming apparatus. Further, it refers to at least process means, developing means and an electrophotographic photosensitive member integrally made into a cartridge which is made detachably mountable to the main body of an electrophotographic image forming apparatus.
Also, the electrophotographic image forming apparatus uses the electrophotographic image forming process to form an image on a recording medium. For example, it covers an electrophotographic copying machine, an electrophotographic printer (such as an LED printer or a laser beam printer), an electrophotographic facsimile apparatus and an electrophotographic word processor.
2. Description of Related Art
In an electrophotographic image forming apparatus, there has heretofore been adopted a process cartridge system in which an electrophotographic photosensitive member and process means for acting on the electrophotographic photosensitive member are integrally made into a cartridge which is made detachably mountable to the main body of the image forming apparatus. According to this process cartridge system, a user himself can effect the maintenance of the apparatus without resort to a serviceman and therefore, operability could be markedly improved. So, this process cartridge system is widely used in electrophotographic image forming apparatuses.
An electrophotographic image forming apparatus of such a cartridge type is of such a structure in which only a cartridge matching in function with the main body of the image forming apparatus can be mounted.
That is, if an attempt is made to mount a cartridge not matching in function with the main body of an image forming apparatus, the design of the cartridge side or the main body side of the apparatus is such that the cartridge cannot be mounted. That is, the cartridge or the main body of the apparatus has a wrong insertion preventing function. The function of the cartridge differs depending on the specification, type, etc., of the apparatus. On the other hand, there are cartridges similar in appearance due to the commonness or the like of the their parts even if they are not fit for image formation in that apparatus. Therefore, if the erroneous mounting of a cartridge having no compatibility should be done, not only is good image formation not effected, but also trouble with the apparatus may be caused.
So, in the electrophotographic image forming apparatus, a construction for determining the compatibility of cartridges has heretofore been proposed and put into practice. There is known, for example, a method using a sensor for discriminating compatibility, or a driving mechanism or the like which can mesh with only the driven gear of a matching process cartridge.
According to the conventional art, however, if a sensor for the judgment of compatibility is to be used, an expensive sensor for discrimination will be required. Also, it will be necessary to mount a part for operating the sensor also on the cartridge side, and this will result in an increase in cost.
Also, in the case of a construction for giving an incompatible function by the meshing engagement between gears, compatibility is discriminated near the mounted position of the cartridge. Therefore, the timing for the discrimination of compatibility is delayed.
The present invention has been made in view of the above-noted unsolved problem peculiar to the conventional art and an object thereof is to provide an electrophotographic image forming apparatus and a process cartridge which can reliably detect the incompatibility of the process cartridge by a simple construction.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus having a wrong mount preventing function of high reliability for the process cartridge.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus which can prevent a process cartridge not matching in function with the main body of the electrophotographic image forming apparatus from being mounted on a mounting portion provided in the main body of the apparatus.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus which enables only a cartridge matching in function with the main body of the electrophotographic image forming apparatus to be mounted on a mounting portion provided in the main body of the apparatus.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus which can prevent a process cartridge not matching in function with the main body of the electrophotographic image forming apparatus from being mounted on a mounting portion provided in the main body of the apparatus, by a simple construction.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus which permits a process cartridge matching in function with the main body of the electrophotographic image forming apparatus to be mounted on a mounting portion provided in the main body of the apparatus and in which a process cartridge not matching in function with the main body of the apparatus is hampered from being mounted on the mounting portion, by a portion of the process cartridge contacting a portion of the main body of the apparatus.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus which can prevent a process cartridge not matching in function with the main body of the electrophotographic image forming apparatus from being mounted on a mounting portion provided in the main body of the apparatus, by a shutter contacting a portion of the main body of the apparatus.
Another object of the present invention is to provide an electrophotographic image forming apparatus comprising a cartridge mounting portion for detachably mounting thereon a process cartridge provided with an electrophotographic photosensitive member, process means for acting on the electrophotographic photosensitive member, a shutter having a photosensitive member protecting portion for protecting the photosensitive member and movable between a protecting position for protecting the photosensitive member and a retracted position retracted from the protecting position to thereby expose the photosensitive member, and a shutter moving portion for moving the shutter from the protecting position to the retracted position, guide means for guiding the cartridge when the cartridge is to be mounted on the mounting portion, shutter opening means for coming into engagement with the shutter moving portion when the cartridge is guided by the guide means and is moved along a movement path toward the mounting portion, to thereby open the shutter from the protecting position to the retracted position, a wrong insertion preventing engagement portion adapted to be engaged with the shutter moving portion on the upstream side of an engagement position in which the shutter moving portion and the shutter opening means are engaged with each other, in the mounting direction in which the cartridge is mounted on the mounting portion when a cartridge not matching in function with the main body of the apparatus is inserted in the main body of the apparatus, to thereby open the shutter, and a main body shutter abutting portion adapted to abut against the shutter moved toward the retracted position by the shutter moving portion being engaged with the wrong insertion preventing engagement portion, to thereby restrict the insertion of the cartridge.
Another object of the present invention is to provide a process cartridge comprising an electrophotographic photosensitive member, process means for acting on the photosensitive member, a shutter having a photosensitive member protecting portion for protecting the photosensitive member and movable between a protecting position for protecting the photosensitive member and a retracted position retracted from the protecting position to thereby expose the photosensitive member, a shutter moving portion for coming into engagement with shutter opening means provided in the main body of an electrophotographic image forming apparatus when the cartridge is mounted on the main body of the apparatus, to thereby move the shutter from the protecting position to the retracted position, and adapted to be engaged with a wrong insertion preventing engagement portion provided in the main body of the apparatus, on the upstream side of an engagement position in which the shutter moving portion and the shutter opening means are engaged with each other, in the mounting direction in which the cartridge is mounted on the main body of the apparatus when the cartridge is inserted into the main body of the apparatus which does not match in function with the cartridge, to thereby move the shutter from the protecting position to the retracted position, and a cartridge shutter abutting portion provided on the shutter for abutting against a main body shutter abutting portion provided in the main body of the apparatus to restrict the insertion of the cartridge into the main body of the apparatus when the shutter is moved toward the retracted position by the shutter moving portion being engaged with the wrong insertion preventing engagement portion.